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Rhodium-catalyzed ring-opening coupling of 2,3-dihydrofuran/benzofuran with organometallic reagents to give Z-homoallylic alcohols and E-stilbenoids was reported.

Advanced maternal age is characterized by declines in the quantity and quality of oocytes in the ovaries, and the aging process is accompanied by changes in gut microbiota composition. However, little is known about the relationship between gut microbiota and ovarian aging. By using fecal microbiota transplantation (FMT) to transplant material from young (5-week-old) into aged (42-week-old) mice, we find that the composition of gut microbiota in FMT-treated mice presents a "younger-like phenotype" and an increase of commensal bacteria, such as Bifidobacterium and Ruminococcaceae. Moreover, the FMT-treated mice show increased anti-inflammatory cytokine IL-4 and decreased pro-inflammatory cytokine IFN-γ. Fertility tests for assessing ovarian function reveal that the first litter size of female FMT-treated mice is significantly higher than that of the non-FMT group. Morphology analysis demonstrates a dramatic decrease in follicle atresia and apoptosis as well as an increase in cellular proliferation in the ovaries of the FMT-treated mice. Our results also show that FMT improves the immune microenvironment in aged ovaries, with decreased macrophages and macrophage-derived multinucleated giant cells (MNGCs). These results suggest that FMT from young donors could be a good choice for delaying ovarian aging.

Elucidation of individual Notch protein biology in specific cancer is crucial to develop safe, effective, and tumor-selective Notch-targeting therapeutic reagents for clinical use [1]. Here, we explored the Notch4 function in triple-negative breast cancer (TNBC). We found that silencing Notch4 enhanced tumorigenic ability in TNBC cells via upregulating Nanog expression, a pluripotency factor of embryonic stem cells. Intriguingly, silencing Notch4 in TNBC cells suppressed metastasis via downregulating Cdc42 expression, a key molecular for cell polarity formation. Notably, downregulation of Cdc42 expression affected Vimentin distribution, but not Vimentin expression to inhibit EMT shift. Collectively, our results show that silencing Notch4 enhances tumorigenesis and inhibits metastasis in TNBC, indicating that targeting Notch4 may not be a potential strategy for drug discovery in TNBC.

A novel rhodium-catalyzed formal [2 + 2 + 1] annulation of alkynes with arylboronic acids to produce 1,1-disubstituted 1(H)-indenes is developed.

In mammals, ovarian function is dependent on the primordial follicle pool and the rate of primordial follicle activation determines a female's reproductive lifespan. Ovarian ageing is characterised by chronic low-grade inflammation with accelerated depletion of primordial follicles and deterioration of oocyte quality. Macrophages (Mφs) play critical roles in multiple aspects of ovarian functions; however, it remains unclear whether Mφs modulate the primordial follicle pool and what is their role in ovarian ageing. Here, by using super- or naturally ovulated mouse models, we demonstrated for the first time that ovulation-induced local inflammation acted as the driver for selective activation of surrounding primordial follicles in each estrous cycle. This finding was related to infiltrating Mφs in ovulatory follicles and the dynamic changes of the two polarised Mφs, M1 and M2 Mφs, during the process. Further studies on newborn ovaries cocultured with different subtypes of Mφs demonstrated the stimulatory effect of M1 Mφs on primordial follicles, whereas M2 Mφs maintained follicles in a dormant state. The underlying mechanism was associated with the differential regulation of the Phosphatidylinositol 3-kinase/Mechanistic target of rapamycin (PI3K/mTOR) signaling pathway through secreted extracellular vesicles (EVs) and the containing specific miRNAs miR-107 (M1 Mφs) and miR-99a-5p (M2 Mφs). In aged mice, the intravenous injection of M2-EVs improved ovarian function and ameliorated the inflammatory microenvironment within the ovary. Thus, based on the anti-ageing effects of M2 Mφs in old mice, M2-EVs may represent a new approach to improve inflammation-related infertility in women.

The pyridylation of alkynes with pyridylboronic acids is realized under rhodium catalysis. Chemodivergent pyridylation products, including alkenylpyridines produced via the hydropyridylation pathway and cyclopenta[

In order to select the cells in vitro, identify the selected cells and trace the selected cells in small animal, we establish a multimodal imaging tool pProTG. We fused enhanced green fluorescent protein, Puromycin N-acetyltransferase and Firefly Luciferase to construct a multimodal imaging tool pProTG, which have ability of selecting the positive cells by puroR, identifying the selected cells by EGFP and imaging the cells in small animal by Fluc. Our established multimodal imaging tool can be used to select the targeted cells in vitro and trace the cells in vivo.

The rhodium-catalyzed controllable diverse arylation of 2,5-dihydrofuran with arylboronic acids is reported. By fine-tuning of the reaction conditions, four different ring-opening or oxidative aryl...

A chemodivergent synthesis of two series of spirochromans depending on the catalytic system was developed. Starting from diarylideneacetones and organoboronic acids, asymmetric rhodium catalysis le...

Background Over 100 mutations in the SRD5A2 gene have been identified in subjects with 46,XY disorder of sex development (DSD). Exploration of SRD5A2 mutations and elucidation of the molecular mechanisms behind their effects should reveal the functions of the domains of the 5α-reductase 2 enzyme and identify the cause of 46,XY DSD. Previously, we reported a novel compound heterozygous p.Q6X/p.H232R mutation of the SRD5A2 gene in a case with 46,XY DSD. Whether the compound heterozygous p.Q6X/p.H232R mutation in this gene causes 46,XY DSD requires further exploration. Methods The two 46,XY DSD cases were identified and sequenced. In order to identify the source of the compound heterozygous p.Q6X/p.H232R mutation, the parents, maternal grandparents, and maternal uncle were sequenced. Since p.Q6X mutation is a nonsense mutation, p.H232R mutation was transfected into HEK293 cells and dihydrotestosterone (DHT) production were analyzed by liquid chromatography–mass spectrometry (LC–MS) for 5α-reductase 2 enzyme activities test. Apparent michaelis constant (Km) were measured of p.H232R mutation to analyze the binding ability change of 5α-reductase 2 enzyme with testosterone (T) or NADPH. Results The sequence results showed that the two 46,XY DSD cases were the compound heterozygous p.Q6X/p.H232R mutation, of which the heterozygous p.Q6X mutation originating from maternal family and heterozygous p.H232R mutation originating from the paternal family. The function analysis confirmed that p.H232R variant decreased the DHT production by LC–MS test. The Km analysis demonstrated that p.H232R mutation affected the binding of SRD5A2 with T or NADPH. Conclusions Our findings confirmed that the compound heterozygous p.Q6X/p.H232R mutation in the SRD5A2 gene is the cause of 46,XY DSD. p.H232R mutation reduced DHT production while attenuating the catalytic efficiency of the 5α-reductase 2 enzyme.

Background: Over 100 mutations in SRD5A2 gene have been identified in subjects with 46,XY DSD. Exploring SRD5A2 mutation and elucidating its molecular mechanism will find the domains function of 5α-reductase 2 enzyme and identify the cause of 46,XY DSD. Previously, we reported a novel compound heterozygous p.H232R/p.Q6X mutation of SRD5A2 gene in a case with 46,XY DSD. Whether the compound heterozygous p.Q6X/p.H232R mutation in SRD5A2 gene causes 46,XY DSD occurrence is needed to be further explored. Results: In order to clarify the cause of 46,XY DSD in the case’s family, SRD5A2 sequencing were performed. The heterozygous p.H232R mutation were identified in the case’s father, so we concluded that the heterozygous p.H232R mutation originated from paternal family and didn’t cause 46,XY DSD occurrence. The heterozygous p.Q6X mutation were identified in the case’s mother, maternal uncle and maternal grandfather, indicating that the heterozygous p.Q6X mutation descended from maternal family and didn’t cause 46,XY DSD occurrence. In order to clarify p.H232R mutation in SRD5A2 on DHT production, p.H232R mutant SRD5A2 plasmids were transfected with HEK293 cells and LC-MS detected that DHT production decreased compared with wild-type SRD5A2 infected ones.Conclusions: Our findings confirmed that the compound heterozygous p.Q6X/p.H232R mutation in SRD5A2 gene is the cause of 46,XY DSD. p.H232R mutation reduced DHT production while attenuated 5α-reductase 2 enzymatic catalytic efficiency.

An expeditious synthetic route to 1,1-disubstituted indenes from propargyl alcohols and organoboronic acids was developed under rhodium catalysis, and selective 1,4-rhodium migration over β-oxygen elimination was involved as the key step. DPEphos was found to be crucial to promote the transformation, and density functional theory (DFT) calculations indicated that DPEPhos can lower the relative energy of the key intermediate on the 1,4-migration path, leading to the unusual selectivity.

Growth and differentiation factor 11 (GDF11) is a member of the transforming growth factor β superfamily. Previous studies have shown that GDF11 decreases with age and has antiaging effects; however, such reports are controversial. We choose 152 subjects covering a large age range (2 hours to 75 years) to measure serum GDF11. Twenty-two hematological variables and 13 biochemical values were measured. Pearson’s analysis found a significant correlation between GDF11 and age (p = .0000, r = .4898), as well as serum creatinine, uric acid, triglycerides, red blood cell count, hemoglobin, hematocrit, and platelet volume distribution width. GDF11 negatively correlated with aspartate transaminase, white blood cell count, platelet count, lymphocyte count, monocyte count, mean platelet volume, and plateletcrit. Interestingly, we found GDF11 increases in people aged 20–30 years, holds steady in people aged 30–50 years, and increases in people older than 50 years. The results suggest that GDF11 serves different roles along the life span. The current actual evidence supports that GDF11 is helpful to promote aging.

Oil absorption by macroporous absorbents has been recognized as an easy, efficient, economical and environment-friendly method in such fields as oil pollution control, oil-water separation, and solidification of liquid fuels/hazardous. In this study, Carbonized asphalt-melamine sponge (CAMS) was prepared by the combination of dip-coating melamine sponge with asphalt/water emulsion and then mild carbonization at 500 °C. The produced CAMS presented high oil-absorption capacity and good recyclability, water-repellence, fire resistance, flexible compressibility and low density. Its chloroform absorption capacity can reach 246 g g−1, significantly higher than that of most of other reported oil absorbents. CAMS is verified as oil-absorbent material with great commercial development potentials that can be massively produced via green and economic process, using no organic solvents or harmful solutions while lowering manufacture costs.

The enantioselective synthesis of a series of C2 -symmetric 3,3'-diarylated 1,1'-spirobiindane-7,7'-diols (3,3'-diaryl-SPINOLs) was developed by sequential Rh-catalyzed twofold asymmetric conjugate arylation/BF3 -promoted diastereoselective spirocyclization (>20:1 d.r. and >99 % ee for all examples). Some phosphoramidite ligands were prepared from the 3,3'-Ph-SPINOL and applied to several catalytic asymmetric reactions, and the 3,3'-diarylated ligands showed higher enantioselectivities than the privileged nonsubstituted ligands.

A general method to access diverse chiral phenols by rhodium-catalyzed asymmetric conjugate arylation using hydroxylated arylboronic acids in ethanol was developed. Recycling of the rhodium catalyst by flash chromatography on silica gel was feasible in this system. The synthetic utility of the strategy was demonstrated by efficient synthesis of chiral drug tolterodine.

ObjectiveThe expression of Wnt7a in colorectal cancer tissues and cell lines was analyzed, and the effect of Wnt7a on the proliferation of colorectal cancer cells was studied, so as to confirm the relationship between Wnt7a and the occurrence and development of colorectal cancer.Methods(1) Immunohistochemical method was used to compare the expression of Wnt7a in different tissues and its relationship with the clinicopathology of colorectal adenocarcinoma. (2) The expression levels of Wnt7a in colorectal cancer cell lines HT-29 and HCT 116 were detected by qRT-PCR. (3) The down-regulated Wnt7A expression vector was constructed, and the down-regulated Wnt7A expression cell line was established. The regeneration ability of cancer cells was detected by stem cell ball formation assay, and the influence of plate cloning assay on the proliferation ability of colorectal cancer cells was detected.Results(1) The positive rates of Wnt7a in normal colorectal mucosa, colorectal adenoma and colorectal adenocarcinoma tissues gradually increased,Wnt7a are closely related to the degree of colorectal adenocarcinoma differentiation, lymph node metastasis and Duke stage. (2) The expression level of Wnt7a in colorectal cancer cells was higher than that in normal colorectal epithelial cells. (3) The down-regulation of Wnt7A reduced the proliferation ability of colorectal cancer cells.ConclusionsWnt7a promotes the occurrence and development of colorectal adenocarcinoma.

Cerebrospinal fluid-touching neurons (CSF-cNs) exist in the region surrounding the central canal of the spinal cord, which locate in the adult neurogenic niche. Previous research showed that CSF-cNs expressed the molecular markers of immature neural cells in vivo. Here, we explored the potential of CSF-cNs as neural stem cell in intro. We first found that PKD2L1+ CSF-cNs, isolating by FACS using the molecular marker PKD2L1 of CSF-cNs, expressed neural stem cells markers like Nestin, Sox2, and GFAP by immunofluorescence staining. PKD2L1+ CSF-cNs were able to form neurospheres and passaged in vitro. Immunofluorescence staining showed that the neurospheres forming by PKD2L1+ CSF-cNs also expressed neural stem cell markers Nestin, Sox2 and GFAP. The neurospheres expressed proliferation markers Ki67 and PCNA by immunofluorescence staining, indicating that the neurospheres forming by PKD2L1+ CSF-cNs were proliferative. The neurospheres, forming by CSF-cNs, had the ability of differentiation into neurons, astrocytes, and oligodendrocytes. Collectively, our data suggested that PKD2L1+ CSF-cNs have the properties of neural stem cells in vitro and may provide a promising approach for the repair of spinal cord injury.

Diboron-mediated rhodium-catalyzed transfer hydrogenation of functionalized arenes is reported. In addition to good functional group tolerance, the reaction features operational simplicity and controllable chemoselectivity. The general applicability of this procedure is demonstrated by the selective hydrogenation of a range of arenes, including functionalized benzenes, biphenyls, and polyaromatics.

The enantioselective synthesis of 2-amino-4H-chromenes via the cascade rhodium-catalysed conjugate addition/hetero Thorpe–Ziegler reaction is reported. Moderate to good yields (up to 98%) and high enantioselectivities (up to 92% ee) were obtained with a chiral diene-coordinated rhodium complex as the catalyst. This protocol remedies the methodological deficiency in the asymmetric synthesis of 4-aryl 2-amino-4H-chromenes.

Background: Colorectal cancer is one of the most common malignant tumors in China, and the number of new cases and the number of cases of deaths has increased annually. However, its pathogenesis is still unclear. Wnt7a is a member of the wingless-type MMTV integration site family, and it plays an important role in tumorigenesis and development by controlling cell proliferation and differentiation as a secreted glycoprotein. Whether Wnt7a has the properties of an oncogene or not is an important focus for future research as this target has diverse roles in different tumors.Methods: Wnt7a protein expression in normal colorectal mucosa and colorectal tumors was detected via immunohistochemistry and Western blot analysis. Univariate and multivariate analyses were used to explore the associations between Wnt7a staining score and various clinical parameters.Results: Wnt7a was strongly expressed in colorectal cancer tissues but weakly expressed in adjacent normal mucosa and colorectal adenomas. The level of Wnt7a expression was correlated with lymph node involvement (P < 0.001), Duke stage (P < 0.001), and cell differentiation (P < 0.001). Knockdown of Wnt7a inhibits proliferation of colon cancer cells and inhibits the ability of both colon cancer cell lines to migrate.Conclusions: Collectively, our results present evidence that Wnt7a is associated with an unfavorable prognosis of colorectal cancer.

Mesenchymal stem cells (MSCs) have the ability of differentiating into osteoblasts. Elucidating the molecular mechanisms of MSC differentiation into osteoblasts may provide novel therapeutic strategies for bone‑related diseases. Increasing evidence has confirmed that Wnt signaling plays the key role in osteoblast differentiation; however, the role of individual Wnt proteins in osteogenesis needs to be investigated. The present study thus aimed to explore the role of Wnt7a in bone formation. For this purpose, human bone‑derived MSCs were identified by flow cytometry and the cell differentiation potential, including osteogenic and adipogenic differentiation was examined. In order to explore the role of Wnt7a in MSC osteogenic differentiation, Wnt7a expression was measured at the mRNA and protein level following treatment with the osteogenic inducer, bone morphogenetic protein (BMP)4/7, and following the induction of osteogenic or adipogenic differentiation. The ectopic expression of Wnt7a in MSCs was confirmed and its influence on MSC osteogenic differentiation was detected using osteocyte markers and by Alizarin Red S staining. Mechanistically, the influence of Wnt7a on Runt‑related transcription factor 2 (RUNX2) expression was examined at the mRNA and protein level. The regulatory effects of Wnt7a on RUNX2 promoter activities were examined by promoter reporter assay, and by examining the binding of TCF1, a downstream target of Wnt, to the RUNX2 promoter by ChIP assay. The results revealed that the knockdown of Wnt7a in MSCs decreased the expression of osteocyte markers and inhibited osteogenic differentiation. In accordance, the overexpression of Wnt7a in MSCs increased the expression of osteocyte markers and promoted osteogenic differentiation. Mechanistically, the knockdown of Wnt7a in MSCs reduced RUNX2 expression and the overexpression of Wnt7a in MSCs promoted RUNX2 expression. Furthermore, it was confirmed that Wnt7a regulated RUNX2 promoter activities by promoter report assay, and by examining the binding of TCF1 to the RUNX2 promoter by ChIP assay. On the whole, the present study demonstrates that Wnt7a plays a key role in MSC differentiation into osteoblasts and the findings presented herein may provide a promising therapy target for bone‑related diseases.

Purpose: Clinical success of precision medicine is severely limited by de novo or acquired drug resistance. It remains a clinically unmet need to treat these patients. Tumor suppressor genes (TSGs) play a critical role in tumorigenesis and impact the therapeutic effect of various treatments. Experimental Design: Using clinical data, in vitro cell line data and in vivo mouse model data, we revealed the tumor suppressive role of Clusterin in lung cancer. We also delineated the signaling cascade elicited by loss of function of CLU in NSCLC cells and tested precision medicine for CLU deficient lung cancers. Results: CLU is a potent and clinically relevant TSG in lung cancer. Mechanistically, CLU inhibits TGFBR1 to recruit TRAF6/TAB2/TAK1 complex and thus inhibits activation of TAK1- NF-κB signaling axis. Lung cancer cells with loss of function of CLU show exquisite sensitivity to TAK1 inhibitors. Importantly, we show that a significant portion of Kras mutation positive NSCLC patients are concurrently deficient of CLU and that TAK1 kinase inhibitor synergizes with existing drugs to treat this portion of lung cancers patients. Conclusions: Combinational treatment with TAK1 inhibitor and MEK1/2 inhibitor effectively shrank Kras mutation positive and CLU deficient NSCLC tumors. Moreover, we put forward a concept that loss of function of a TSG rewires signaling network and thereby creates an Achilles' heel in tumor cells which could be exploited in precision medicine.

Controllable synthesis of a variety of allenic alcohols and 2,5-dihydrofurans by rhodium(I)-catalyzed arylative transformations of propargylic diols is reported. The hydroxorhodium catalyst was found to play dual role: it catalyzed the arylation/dehydroxylation reaction of propargylic diols to afford allenic alcohols, and besides, it could convert to a cationic rhodium species in situ, which catalyzed the intramolecular hydroalkoxylation of allenic alcohols to form dihydrofurans. Remarkably, generation of the cationic rhodium species is dependent on the arylboron reagent used. Thus, the controllable synthesis is achieved by simply changing the arylboron reagent.

An unprecedented rhodium-catalyzed homocoupling reaction of γ-alkylated tert-propargylic alcohols is reported, and 2-alkynylated buta-1,3-diene or 2-alkynylated hexa-1,3,5-triene are generated selectively. Multiple β-eliminations, including sequential β-carbon, β-hydrogen, and β-oxygen eliminations from the corresponding rhodium intermediates, are assumed to be involved during the reaction process.

Diverse tetrasubstituted allenes are obtained selectively by the reaction of tert-propargylic alcohols and arylboroxines under rhodium catalysis. The reaction is assumed to proceed through an arylation/dehydroxylation process, which involves β-hydroxide elimination of a β-hydroxy alkenyl-rhodium intermediate that is generated by regioselective arylrhodation of the tert-propargylic alcohol. In addition, when enantioenriched propargylic alcohol was used to prepare optically active allene, high efficiency of central-to-axial chirality transfer was observed. The application of current method to structural modification of pharmaceutical drugs was also showcased by a highly diastereoselective transformation of mifepristone.

Background Ethanol causes developmental neurotoxicity partly by blocking adhesion mediated by the L1 neural cell adhesion molecule. This action of ethanol is antagonized by femtomolar concentrations of the neuropeptide NAPVSIPQ (NAP), an active fragment of the activity-dependent neuroprotective protein (ADNP). How femtomolar concentrations of NAP antagonize millimolar concentrations of ethanol is unknown. L1 sensitivity to ethanol requires L1 association with ankyrin-G; therefore, we asked whether NAP promotes the dissociation of ankyrin-G and L1. Methods L1–ankyrin-G association was studied using immunoprecipitation, Western blotting, and immunofluorescence in NIH/3T3 cells transfected with wild-type and mutated human L1 genes. Phosphorylation of the ankyrin binding motif in the L1 cytoplasmic domain was studied after NAP treatment of intact cells, rat brain homogenates, and purified protein fragments. Results Femtomolar concentrations of NAP stimulated the phosphorylation of tyrosine-1229 (L1-Y1229) at the ankyrin binding motif of the L1 cytoplasmic domain, leading to the dissociation of L1 from ankyrin-G and the spectrin-actin cytoskeleton. NAP increased the association of L1 and EphB2 and directly activated EphB2 phosphorylation of L1-Y1229. These actions of NAP were reproduced by P7A-NAP, a NAP variant that also blocks the teratogenic actions of ethanol, but not by I6A-NAP, which does not block ethanol teratogenesis as potently. Finally, knockdown of EPHB2 prevented ethanol inhibition of L1 adhesion in NIH/3T3 cells. Conclusions NAP potently antagonizes ethanol inhibition of L1 adhesion by stimulating EphB2 phosphorylation of L1-Y1229. EphB2 plays a critical role in synaptic development; its potent activation by NAP suggests that ADNP may mediate synaptic development partly by activating EphB2.

Background: Mesenchymal stem cells (MSCs) have the ability of differentiating into bone. Elucidating the molecular mechanisms of MSC differentiation into bone could provide new therapeutic strategy for bone-related diseases. Growing evidence confirmed that Wnt signal played the key role in osteoblast differentiation, but the role of individual Wnt protein in osteogenesis need to be investigated. Here, we aim to explore the role of Wnt7a in bone formation. Methods: Human bone-derived MSCs were identified by flow cytometry and its differentiation potentials. Wnt7a expression were measured by osteogenic inducer BMP4/7 treatmemt, osteogenenic or adipogenic differentiation. The influence of Wnt7a ectopic expression in MSCs on osteogenic differentiation were detected by osteocyte markers and Alizarin Red S staining. The mechanismof Wnt7a regulating Runx2 expression were detected by promoter reporter assay and ChIP assay. Findings: Our results showed that knockdown of Wnt7a in MSCs decreased the expression of osteocyte markers and inhibited osteogenic differentiation. Concordantly, the overexpression of Wnt7a in MSCs increased the expression of osteocyte marker and promoted osteogenic differentiation. Mechanistically, the knockdown of Wnt7a in MSCs reduced Runx2 expression and the overexpression of Wnt7a in MSCs promoted Runx2 expression. Furtherly, we confirm that Wnt7a regulated Runx2 promoter activities by promoter report assay, and TCF1, a downstream target of Wnt, binding to the Runx2 promoter by ChIP assay. Interpretation: Our research confirmed that Wnt7a played a key role in MSCs differentiation into bone and this maybe provide a promising therapy target for bone-related disease. Funding Statement: This work was supported with funding from the National Natural Science Foundation of China (No. 81860516), the start-up grant from the Affiliated Hospital of Guizhou Medical University (No. I201802), Guizhou science and Technology Department (No. 2016J7234), Guizhou science and Technology Department (No. 2014LH7149), the National Natural Science Foundation of China (No.81460448), the R&D infrastructure and facility Development and Program of Guizhou (No. 20154005). Declaration of Interests: The authors declare no competing financial interests. Ethics Approval Statement: Human bone tissues from surgical resection were from patients in the Department of Orthopedics of the Affiliated Hospital of Guiyang Medical University. All work and protocols were under the guidelines by the Human Care and Use Committee of Guiyang Medical University. Each patient wrote informed consent before the preparation of the bone tissues.

Benefiting from the natural nano-size graphene-structure in natural asphaltene material, a facile one-pot route, mild chemical oxidation of low-value petroleum asphaltene followed by routine ammonium neutralization, is presented to produce high quality graphene quantum dots (GQDs). The asphaltene-derived GQDs possess a variety of oxygen-containing and nitrogen-containing functional groups such as carboxyl, hydroxyl, amine, and nitro groups. They present such excellent fluorescence properties as stable ability to retain strong green fluorescence within a relative broad excitation range in a bio-suitable pH range of 4–7, high photoluminescence quantum yield of 18% and good fluorescent stability against photobleaching. And they are much smaller and thinner than most reported GQDs, displaying good biocompatibility with low cytotoxicity, effective cellular uptake, and excellent fluorescent probe performance for cancer cell imaging.

A new type of planar chiral Shvo catalysts, where the chirality is based solely on different substitution flanking the CO function, was prepared and used for transfer hydrogenation of imines and ketones. The reduction of ketimines represented by N-(1-phenylethylidene)aniline and prochiral ketones such as phenyl trifluoromethyl ketone with 2-propanol was efficiently catalyzed by 0.5 mol% of the chiral Shvo catalyst to give high yields of the corresponding reduction products with the enantioselectivities in the range 45% to 64% ee.

The enantioselective synthesis of a series of C

The first catalytic asymmetric conjugate addition to γ,δ-unsaturated β-dicarbonyl compounds was developed. With a chiral diene-rhodium(I) μ-chloro dimer as the catalyst in toluene/H2O, asymmetric conjugate arylation of γ,δ-unsaturated β-dicarbonyl compounds with arylboronic acids proceeded in high efficiency with excellent enantioselectivities. The generated β-dicarbonyl products are versatile chiral synthons, which can be easily converted to diverse important chiral structures. MOE (Min. of Education, S’pore)

Ethanol causes fetal alcohol spectrum disorders (FASDs) partly by inhibiting cell adhesion mediated by the L1 neural cell adhesion molecule. Ethanol interacts with an alcohol binding pocket in the L1 extracellular domain (ECD), and dephosphorylation of S1248 in the L1 cytoplasmic domain (CD) renders L1 adhesion insensitive to inhibition by ethanol (L1 insensitive). The mechanism underlying this inside-out signaling is unknown. Here we show that phosphorylation of the human L1-CD at S1152, Y1176, S1181, and S1248 renders L1 sensitive to ethanol by promoting L1 coupling with ankyrin-G and the spectrin-actin cytoskeleton. Knockdown of ankyrin-G or L1 mutations that uncouple L1 from ankyrin reduce L1 sensitivity to ethanol, but not methanol, consistent with a small conformational change in the extracellular alcohol binding pocket. Phosphorylation of Y1176 and ankyrin-G coupling with L1 are higher in NIH/3T3 clonal cell lines in which ethanol inhibits L1 adhesion than in ethanol-resistant NIH/3T3 clonal cell lines. Similarly, phosphorylation of Y1176 is higher in C57BL/6J mice that are sensitive to ethanol teratogenesis than in ethanol resistant C57BL/6N mice. Finally, polymorphisms in genes that encode ankyrin-G and p90rsk, a kinase that phosphorylates S1152, are linked to facial dysmorphology in children with heavy prenatal ethanol exposure. These findings indicate that genes that regulate L1 coupling to ankyrin may influence susceptibility to FASD.-Dou, X., Menkari, C., Mitsuyama, R., Foroud, T., Wetherill, L., Hammond, P., Suttie, M., Chen, X., Chen, S.-Y., Charness, M. E., Collaborative Initiative on Fetal Alcohol Spectrum Disorders. L1 coupling to ankyrin and the spectrin-actin cytoskeleton modulates ethanol inhibition of L1 adhesion and ethanol teratogenesis.

Asymmetric arylation of γ,δ-unsaturated β-ketophosphonates with arylboronic acids is reported. By using the (R)-diene* ligated rhodium(I) chloride complex as a catalyst under none basic conditions, the corresponding β-ketophosphonates bearing a δ-chiral center were obtained in high yields (up to 99%) with good to excellent enantioselectivities (up to >99% ee). The enantioenriched products can be readily converted to diverse chiral β′-aryl enones by the Horner–Wadsworth–Emmons reaction. MOE (Min. of Education, S’pore)

Asymmetric conjugate alkynylation of cyclic α,β-unsaturated carbonyl compounds (ketones, esters, and amides) was realized by use of diphenyl[(triisopropylsilyl)ethynyl]methanol as an alkynylating reagent in the presence of a rhodium catalyst coordinated with a new chiral diene ligand (Fc-bod; bod=bicyclo[2.2.2]octa-2,5-diene, Fc=ferrocenyl) to give high yields of the corresponding β-alkynyl-substituted carbonyl compounds with 95-98% ee.

For the purpose of revealing the promoting role of water on the reactivity of the supported Pt/FeOx catalyst in the low-temperature oxidation of CO, in situ diffuse reflectance infrared Fourier transform (DRIFT) spectra were conducted to study the adsorption properties of CO under various conditions. In the case of without water (CO + O-2), CO could be preferentially adsorbed on the active Pt sites, and then strongly adsorbed on the Fe3+ sites, which might considerably inhibit the ability for O-2 activation, and result in the decrease of reactivity of Pt/FeOx for low-temperature oxidation of CO. For the CO oxidation under wet condition (CO + O-2 + H2O), coadsorption of water and oxygen was observed, which could form surface oxygen/hydroxyls species, and significantly inhibit the adsorption of CO on the Fe3+ sites, thus avoiding the deep reduction of the active Fe3+ sites located at the boundaries between FeOx and Pt nanoparticles. In this case, the catalytic redox cycle in the active Fe3+ sites (mainly for O-2 activation) could be easily achieved by the addition of H2O, which finally results in the significant improvement of the activity and stability of the Pt/FeOx catalyst in low-temperature oxidation of CO.

The first example of catalytic asymmetric conjugate alkynylation of β,γ-unsaturated α-ketoesters is reported. By using Rh(I)/(R)-DM-binap complex as the catalyst and diphenyl[(triisopropylsilyl)ethynyl]methanol as the alkynylating reagent, the alkynylation reaction proceeded smoothly to afford α-ketoesters bearing a propargylic chiral center at γ position in good yields with high enantioselectivities.